Step 4: Place 120V loads (largest to smallest): 100% on any phase. Now consider the following wye transformer sizing example: What size transformer (480V to 208Y/120V, 3-phase) would you need for the ...

Let’s show how this all works through an example problem. Question What size primary-only protection overcurrent device and conductor is required for a 45kVA, 3-phase, 480V transformer that is fully ...